The objective of this project is to investigate the manner in which the aging process affects somatomotor activity during the behavioral states of sleep and wakefulness. Our experimental paradigms are oriented to provide basic data relating to the modulation of the membrane potential of spinal cord lumbar motoneurons and the control of these cells by the reticular formation during sleep and wakefulness in age-documented adult and old cats. As the initial step in this endeavor we propose to examine the fundamental electrophysiological characteristics of lumbar and reticular neurons under acute conditions to obtain as broad a perspective of different aspects of neural activity as possible. The proposed studies should allow us to (1) generate a normative fund of information relating to age-related decrements in the functioning of spinal cord motor mechanisms and their control by the reticular formation in acute and chronic conditions and (2) develop correlated morphological data based upon the injection of horseradish perodixase into the lumbar and reticular neurons from which electrophysiological data have been obtained. Alpha motoneurons of the cat lumbar spinal cord are perhaps the most intensively studied class of mammalian nerve cells. Thus, the age-related deficits in different electrophysiological and morphological indices of function in these neurons may provide a microcosm of interrelated time-dependent changes throughout the nervous system. We also hope to generate data that will provide a basis for understanding some of the neuronal processes underlying one of the most debilitating pathologies of old age--Alzheimer's disease. In our old cats we have already found in these "cholinergic" neurons, aged changes which are comparable to those reported in humans suffering from this disease.